Silent gears, etc., and method of manufacture



Sept. 23, 1930'. s. H. CLARK 1,776,619

v v SILENT GEARS ETC., AND METHOD OF MANUFACTURE Filed Sept. 22. 1927 Patented Sept. 23.1930

; UNITED. STA ES PATENT OFFICE enonenn. cmmx, or cmcr nna'rr, 01110, ASSIGNOR To 'IHE ronmrca msuLA'rrom COMPANY, OF CINCINNATI, OHIO, A CORPORATION OF OHIO srmnr cases, are, AND mn'rnon or ms'nurac'runn I Application filed September 22, 1927. Serial No. 221,301.

This invention relates particularly to gearwheels of the silent gear type having non-metallic teeth. Such gears are, at-the present time, manufactured from various non-metallic-substances. A highly satisfactory laminated'product for the'purpose is composed of cloth, or canvas, impregnated with a varnish of bakelite, redmanol, or other phenolic Condensation product, the massbeing compacted and hardened under heat and pressure. 4 One of the main diflicu lties with the use of a laminated produ'ctof the character men- Th1s is particularly true, when the gear is forced onto the shaft under heavy pressure,

which may unintentionally exceed the'elastic limit. In such a case, the material will cold- Attemptsvhave been made to overcome the difliculty mentioned by molding within the laminated disk a complete metal bushing, but

this adds considerably to the cost of the gear-j blank, and requires machining. I

In accordance wifll the present invention,

' disks of bakelite-impregnated fabric are perforated and assembled in a special manner and have associated therewith stamped metal rings which are so I'GIBtQdfitOthB stack of fabric disks that' a gear-blank may beformed in an economical "manner in a heated hydraulic press, such gear-blank having embedded in its hub-portion'the metalli'c disks so firmly anchored to the non-metallic body as to provide a reliable-connection between the gear-blank and a shaft when a press-fit is tioned for gear-blanks, or gears, is'the tendency of the disk to become loose on the shaft.

I flow and the gear will loosen from the shaftn F ig.3, a perspective view of a fabric disk having a perforation of a size adapted to ad- .mlta metallic washer; Fig. 4, a perspective View of one of the metallic washers employed; Fig. 5, a sectional View of afinished with teeth. v I

Referring to Fig. 2,'A designates a fabric disk impregnated with a solution of a ph'enolic condensation: product, such as bakelite,

mounted. Referring to Fig. 3, A designates a similar disk, but having a perforation A large 'gear; and Fig. 6, a broken base view of a finished gear-blank, shown partly provided enough in diameter to admit a metallic washer.

Referring to Fig. 4, B designates a metallic washer having a perforation B of about the to be mounted and having an external diameter corresponding with the diameter of the perforation A The metallic disk B is cut used in connection with the fabric disksshown in Fig. 1.

' In the diagrammatic view shown in Fig. 1,'

the disks A and A are assembled in groups.

For convenience, the groups are bracketedsize. of a shaft upon which the gear-blank is and the number of disks ineach group is apv plied tothe corresponding bracket.

The disks shown in Fig. 1 are arranged in the same relation in which they enter into I the finished gear shown in Fig. 5, the finished gearbeing I designated 0. Thus, reading from right to left on Fig. 1, there are six of the blanks A; then six of the blanks A then one of the blanks A; then three of the blanks A The further arrangement will beunderstood from'the diagram itself.

It will be noted that there are four groups,

each containing three of the disks A Each ofthese four groups of three blanks receives or houses one of the metallic washers B in the.

assembly of the pack for insertion into the heat and pressure, such as is ordinarily employed for producing laminated phenolic condensation products. A suitable pressure is about two thousand pounds per square inch, and a suitable temperature is about 175 C. The article preferably is maintained under heat and pressure until the phenolic condensation product has been converted to the final infusible and substantially insoluble condition. Ordinarily, the hot-pressing operation will require from ten to forty-five minutes, depending upon the size of the gearblank, the temperature employed, etc.

The dies may be of suitable shape to produce the form of gear-blank indicated in Fig. 5. After the blank has been produced, the teeth may be cut, as in the case of an ordinary metal gear.

It will be noted that the use of the fabric disks arranged in the manner shown at the right-hand portion of Fig. 1 enables the dies to form therecess C at one side of the gearblank. ,Also, the dies, when this particular arrangement is employed, effect a certain amount of dishing of the washers B, and this tends to strengthen the bond between the metal washers and non-metallic body of the gear-blank.

It has been found in practice that metallic washers may in this manner be introduced into a gear-blank in such manner as to be come virtually integral with the gear-blank; and when agear-blank thus constructed is pressed onto a. shaft under pressure of several tons, the gear-blank becomes so firmly fixed upon the shaft that there is no liability of its working loose. The gear-blank is shown provided with a central perforation sembly' comprising annular disks of fabric impregnated with aphenolic condensation C to receive the shaft. This preparation may represent the bore of the gear-blank after it has been forced onto a shaft. That is, the finished gear-blank may have a bore represented by the diameters of the perforations A and B; or, if desired, the bore of the press-blank may be trimmed by means of a boring tool, although ordinarily this is unnecessary.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom.

, lVhat I regard as new, and desire to secure by Letters Patent, is:

1. The process 'of producing a gear-blank which comprises: placing in a mold an asproduct, and metallic washers, some of the fabric disks having larger perforations than the others and serving to house said washers; and consolidating the assembly under heat and pressure.

2. The process of producing a gear-blank which comprises: assembling groups of fabric disks having bores of relatively small diameter and interspersed groups of fabric disks having bores of relatively large diameter and metallic washers within some of the larger bores; and consolidating the assembly under heat and pressure.

3. The process of forming a: gear-blank which comprises: assembling alternating groups of disks impregnated with a binder, said groups having bores of different diameters and metallic washers housed in some of the larger bores, the outer groups at the ends of the assembly having small bores; and molding the assembly under heat and pressure.

4. The method of forming an article of th character described which comprises: as sembling groups of fabric disks, impregnated with a phenolic condensation product, said groups having bores of different diameters and being arranged in alternation, and introducing metallic washers within the bores of intermediate groups vof large diameter, the assembly providing an end group of disks having bores of small diameter and an adjacent group of disks having bores of large diameter; and subjecting the assembly to heat and pressure in a mold adapted to dish the body of the article at one side.

5. An article of the character set forth consisting of interspersed groups of fabric disks impregnated with a phenolic condensation product, said groups having bores of different diameters and metallic washers housed in some of the larger bores, all of said groups being consolidated under heat and pressure into an integral body within which said metallic washers are embedded, the inner circumferences of said metallic washers forming a part of the bore of the consolidated body.

'- GEORGE H. CLARK. 

